802.11 Wireless Network Site Surveying and Installation

278 Chapter 11: Performing a WLAN Site Survey

and channel scheme. When the “down” AP comes back on line, the reconfiguration takes

place again.

Although this automatic reconfiguration feature might sound great for a failed AP, if the AP

is intermittent, or the interference that is causing the problem is intermittent, the systems

will go through constant reconfiguration, disrupting normal usage. To prevent the constant

changes to configurations, take care to ensure reconfiguration parameters filter out these

fluctuations and temporary situations.

Site Surveying for Repeater Usage

Repeaters are supported by many of the WLAN products available today. However, the use

of repeaters is recommended in only two scenarios:

• Locations where there is no possible way to wire the device

• If the installation will be temporary

The reason for this limited recommended use of repeaters is that a 50-percent reduction of

bandwidth is typically introduced. The overlap on a repeater and its wired AP partner has

to be, at a minimum, 50 percent. This is required so that the two APs have full

communication with each other (see Figure 11-19).

Figure 11-19 Repeater Overlap

Channel 1

LAN Backbone

Channel 1

Access

Point

Repeater

AP